In the COBIT 2019 Design Guide, it is clearly stated that:
"The more quantitative approach involves numeric mapping tables created for each design factor. The mapping tables quantify the descriptive values associated with each design factor, in order to indicate their correlation with governance and management objectives." These mapping tables typically contain values ranging from zero (0) to four (4), where four indicates maximum relevance of a governance or management objective with that particular design factor value, and zero indicates no relevance.
Reference:COBIT 2019 Design Guide, Section 4.3.1